I got mine direct deposit very early on.
My daughter did not get one. In looking at her 2019 tax year paperwork, she used the foreign income exclusion, which put her US income down to zero. (She need not have, she could have just declared the income and wouldn't have to pay taxes as it was below the standard deduction. But that's what she did.) She had gotten the first stimulus as a direct deposit. So it's not as if the IRS didn't have her bank info. The payments were supposed to be based on the 2019 tax year info, I believe. (I haven't checked up on that.) Either that or the fact that she didn't put her bank info on the 1040 for 2019 tax year blew something up in the computer system - even though they had it for the 2018 tax year.
We sent change of address forms to the IRS towards the end of last year, since the Royal Mail does not forward mail back to the USA, so they should have been able to find her if there were questions about her 2019-year tax forms. They are not sending a paper check or a debit card, either. Her info online on the stimulus checker just says "not available" which is, apparently, code for "it ain't coming."
I looked and it seems that these payments are actually advance tax credits that you would otherwise claim on your 2020 IRS return. One of the caveats is that you don't get a payment if you are a dependent adult, or if the IRS thinks you are likely to be a dependent adult. (The first payment need not be refunded if you do end up as a dependent adult, but it's not clear about the second one - different pieces of legislation.)
This year I most definitely am claiming head-of-household with an adult dependent (my daughter). I am thinking that perhaps they looked at her paperwork, saw the zero income, and assumed this might be the case. (?) She cannot retroactively claim that second payment on her 1040 this year as she has had no income - although she could file a 1040, as a dependent she's not eligible for the credit so she can't claim it on the 1040 as all the advice being touted on various websites says to do. Which is ok, I guess. She's not legally entitled to it.